Solid-state image pickup apparatuses using the CMOS technique are known, and among these, a passive pixel sensor (PPS) type solid-state image pickup apparatus is known. The PPS type solid-state image pickup apparatus includes a photodetecting section where PPS type pixel units including photodiodes for generating charges of amounts according to incident light intensities are two-dimensionally arrayed in M rows and N columns, accumulates, in a capacitor of an integrating circuit, charges generated in the photodiode in response to light incidence in each pixel unit, and outputs a voltage value according to the accumulated charge amount.
Generally, an output terminal of each of the M pixel units of each column is connected with an input terminal of an integrating circuit provided corresponding to the column via a readout wiring provided corresponding to the column. And, in sequence from the first row to the M-th row and row by row, charges generated in the photodiodes of the pixel units are input to a corresponding integrating circuit through a corresponding readout wiring, and a voltage value according to the charge amount is output from the integrating circuit.
The PPS type solid-state image pickup apparatus is used for various purposes, and used, for example, in combination with a scintillator section as an X-ray flat panel also for medical purposes and industrial purposes, and further specifically used also in an X-ray CT apparatus, a microfocus X-ray inspection system, etc. An X-ray inspection system disclosed in Patent Document 1 is a system that images X-rays output from an X-ray generator and transmitted through an inspection object by a solid-state image pickup apparatus to inspect the inspection object, and is capable of imaging X-rays transmitted through the inspection object by the solid-state image pickup apparatus in a plurality of types of imaging modes. These multiple types of imaging modes are mutually different in an imaging region in the photodetecting section.